Embodiments of the present invention relate to a thin film transistor liquid crystal display (TFT-LCD) array substrate, a manufacturing method thereof, a detecting method thereof and a driving method thereof.
A thin film transistor liquid crystal display (TFT-LCD) mainly comprises an array substrate, a color filter substrate and a liquid crystal layer sandwiched between the array substrate and the color filter substrate. Gate lines and data lines are formed on the array substrate. Thin film transistors and pixel electrodes are further formed on the array substrate in a matrix. A black matrix, color resin units and a common electrode are formed on the color filter substrate. The liquid crystal molecules in the liquid crystal layer are orientated under the control of the voltage difference between the pixel electrodes of the array substrate and the common electrode of the color filter substrate. Because of different orientation angles, the light passing through the pixel units varies, and thus different gray levels are represented to display the desirable image.
In manufacturing a TFT-LCD, it is necessary to detect the array substrate in order to secure the product quality. Currently, the TFT-LCD array substrate is detected for example by a simulation cell method. The detecting device employed in this method is a device that utilizes the photoelectric conversion phenomenon and mainly comprises a mirror for reflecting light and a liquid crystal layer provided above the mirror. In detecting, the TFT-LCD array substrate is placed below the mirror with a distance of 12 μm to 20 μm and data signals are inputted into the array substrate. With the cooperation of an imaging system, the detection of the array substrate is accomplished by utilizing the phenomenon that the liquid crystal molecules deflect with the variation of the electric field and by utilizing the photoelectric conversion phenomenon. However, the above detecting device is complex and expensive, and the above detecting method is not flexible enough.
In addition, image sticking is one of the severe problems to be taken care of in a TFT-LCD. During the operation of a TFT-LCD, charges may be accumulated in the alignment layers provided on both sides of the liquid crystal layer and in other micro-structures. The accumulated charges result in an additional voltage difference between the pixel electrode and the common electrode. Thus, the liquid crystal molecules deflect under the additional voltage difference even though no data signal is applied, and in this case, optical rotation effect occurs and image sticking is generated. In addition, when a same image is displayed for a long time period, the liquid crystal molecules are easily to be polarized, and in this case, optical rotation effect also occurs due to the polarized liquid crystal molecules and image sticking is generated as well. Currently, diversifying the materials employed in a TFT-LCD is one of the methods to overcome the defect of image sticking; however, the defect of image sticking cannot be completely eliminated.